1. Field of the Invention
The present invention relates to a wide-angle projection lens.
2. Description of the Related Art
Projectors which adopt LED as a light source have the advantage of small size. However, the light flux of an LED light source is apparently smaller than the traditional high pressure mercury-vapor lamp. So projectors which use an LED light source need to adopt a lens with larger aperture, that is a lens with smaller F-number. Generally, projectors which use high pressure mercury-vapor lamp have a projection lens with smaller aperture, where the F-number is generally larger than 2.4. According, this kind of projection lens is unsuitable for projectors which adopt LED as a light source. On the other hand, for projecting a larger scene within a short projecting length, a short-focus lens, which is a wide-angle lens, is needed. For the two aforementioned reasons, there is a need for a new projection lens with small F-number and large angel of view at the same time to fulfill the market.